I suppose if it were not for defecation messes, you wouldn't think twice about how much she eats?
"Eat just to be eating". Like when we're not hungry, yet we still open a box of chocolates and eat them all? We've proven that humans often eat purrely for pleasure. But it's an inscrutable statement when applied to iguanas. It sounds just like "over-eating".
Time of year, hormones, and return to optimum heat/lighting increase iguana appetites, and we don't have all that figured out, and probably never will.
Decades of observing eating behavior show us that increased appetite is natural and doesn't lead to physical problems, and is common. For all we've ever seen, you treat increased appetite by feeding it without worry.